VI CONTENTS OF VOL. I. SIXTH SERIES. 



Page 



Mr. E. J. Eendtorff on Differential Double Eefraction 539 



Dr. G. Pierce on the Double Refraction of Electric Waves . . 548 

 Prof. E. W. Wood on the Production of a Bright-Line Spec- 

 trum by Anomalous Dispersion and its Application the 



" Elash-Spectrum " 551 



Dr. Q. Majorana on the Eelative Luminous Intensities of 



Sun and Sky 555 



Prof. W. B. Morton on the Propagation of Polyphase Currents 



along a Number of Parallel Wires 563 



Prof. C. Barns on the Change of the Colours of Cloudy Con- 

 densation with the Number of Available Nuclei, and on 



the Effect of an Electric Field 572 



Mr. H. Hilton on van der Waals' Equation 579 



Prof. E. W. Wood on the Propagation of Cusped Waves and 



their Eelation to the Primary and Secondary Focal Lines . 589 

 Prof. J. P. Kuenen on Mixtures of Hydrochloric Acid and 



Methylether 593 



Proceedings of the Geological Society: — 



Prof. T. G. Bonney and the Eev. E. Hill on the Drifts 



of the Baltic Coast of Germany 598 



Dr. Catherine A. Eaisin on certain Altered Bocks from 

 near Bastogne and their Eelations to others in the 



District 599 



Dr. J. W. Evans on a Monchiquite from Mount Girnar, 

 Junagarh (Kathiawar) 600 



NUMBEB VI.— JUNE. 



Dr. S. W. Eichardson and Mr. Louis Lownds on the Mag- 

 netic Properties of the Alloys of Cast-Iron and Aluminium. 



Part II. (Plate VI.) . . 601 



Prof. E. W. Wood on Cyanine Prisms and a New Method of 



exhibiting Anomalous Dispersion 62-1 



Prof. E. W. Wood on a Mica Echelon Grating 627 



Prof. J. S. Tovvnsend and Mr. P. J. Kirkby on Conductivity 

 produced in Hydrogen and Carbonic Acid Gas by the 



Motion of Negatively Charged Ions 630 



Mr. E. Beattie on the Hysteresis of Nickel and Cobalt in a 



Eotating Magnetic Fieid 642 



Dr. F. G. Donnan on a Theory of Colloidal Solution 647 



Mr. C. G. Barkla on the Velocity of Electric Waves along 



Wires 652 



Proceedings of the Geological Society 667 



On the Normal Curve of Errors, by Prof. Karl Pearson .... 670 

 An Error in Dr. Willows's Paper "On the Absorption of Gas 

 in a Crookes Tube," by William Eollins 671 



Index 672 



